title: Allele and Haplotype Diversity of 26 X-STR Loci in Four Nationality Populations from China.
abstract: Haplotype analysis of closely associated markers has proven to be a powerful tool in kinship analysis, especially when short tandem repeats (STR) fail to resolve uncertainty in relationship analysis. STR located on the X chromosome show stronger linkage disequilibrium compared with autosomal STR. So, it is necessary to estimate the haplotype frequencies directly from population studies as linkage disequilibrium is population-specific.
  
  
  
  Twenty-six X-STR loci including six clusters of linked markers DXS6807-DXS8378-DXS9902(Xp22), DXS7132-DXS10079-DXS10074-DXS10075-DXS981 (Xq12), DXS6801-DXS6809-DXS6789-DXS6799(Xq21), DXS7424-DXS101-DXS7133(Xq22), DXS6804-GATA172D05(Xq23), DXS8377-DXS7423 (Xq28) and the loci DXS6800, DXS6803, DXS9898, GATA165B12, DXS6854, HPRTB and GATA31E08 were typed in four nationality (Han, Uigur, Kazakh and Mongol) samples from China (n = 1522, 876 males and 646 females). Allele and haplotype frequency as well as linkage disequilibrium data for kinship calculation were observed. The allele frequency distribution among different populations was compared. A total of 5-20 alleles for each locus were observed and altogether 289 alleles for all the selected loci were found. Allele frequency distribution for most X-STR loci is different in different populations. A total of 876 male samples were investigated by haplotype analysis and for linkage disequilibrium. A total of 89, 703, 335, 147, 39 and 63 haplotypes were observed. Haplotype diversity was 0.9584, 0.9994, 0.9935, 0.9736, 0.9427 and 0.9571 for cluster I, II, III, IV, V and VI, respectively. Eighty-two percent of the haplotype of cluster IIwas found only once. And 94% of the haplotype of cluster III show a frequency of <1%.
  
  
  
  These results indicate that allele frequency distribution for most X-STR loci is population-specific and haplotypes of six clusters provide a powerful tool for kinship testing and relationship investigation. So it is necessary to obtain allele frequency and haplotypes data of the linked loci for forensic application.
authors.affiliation: Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, P.R. China.
authors.forename: Qiu-Ling
authors.initials: QL
authors.lastname: Liu
authors.forename: Jing-Zhou
authors.initials: JZ
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Quan
authors.forename: Hu
authors.initials: H
authors.lastname: Zhao
authors.forename: Ye-Da
authors.initials: YD
authors.lastname: Wu
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Huang
authors.forename: De-Jian
authors.initials: DJ
authors.lastname: Lu
mesh_terms: D044466:Asian People / Q000208:ethnology* / Q000235:genetics*; D002681:China / Q000208:ethnology; D005260:Female; D005787:Gene Frequency; D056426:Genetic Loci; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male